Replacement Boilers

rej@cpintenet.c

Looking to retire in near future so am upgrading everything in our home before I close the shop doors. I started with the heating system but now not sure I did it right.

- Old system - Oil fired boiler with 3 zones controled by zone valves with one Grundfos 3 speed pump (Type: UPS 20-42F) Usually ran the pump on low or medium.

- New system - Dual fuel (Elect. Thermolec B-23/Gas: Munchkin 80M) with the loop pump being a Grundfos single speed Type: UP 26-64.

With the new system I changed from zone valves to Grundfos single speed pumps (Type:15-40) with swing valves just above the pumps. I am wondering if these pumps were large enough or maybe I should not have used the swing valves? My reason for questioning this is that with the new system it just seems the boiler takes (meaning stays on) at least 1/3 longer to heat the same sq ft when compared to the old system. At first I thought I undersized the boiler but with outside temp. at 0 deg F the Elect Thermolec reads a steady 180 deg with only 1 or 2 of the 5 element indicator lights staying on steady, while a 3rd will blink off and on from time to time, it does not seem the boiler is anywhere near maxing out. Of course nearing retirement age, this whole thing could be my imagination to you know

So here are my basic questions:

1 - Are the new pumps equal in gal. per mn and rpm to the old 3 speed pump set on low or med. I do not know much about pumps so could anyone tell me what the gal and rpm is of these pumps? I just ask others for advice about pump sizing.

2 - Was it over kill to place swing valves above the zone pumps and would they restrict the flow?

Pertaining to air in the system, that has been perged at each register as well as other bleeders I put in at high points.

Thank you for any help

Ron

TimNJ

What are you referring to "swing valve"? You mean Flo-control Valve?

#CARRIERMAN

I think what he is talking about is a swing check type check valve. Not quite sure why they used them unless they are pumping a high head. When you add them in you are supposed to change pump gpm to accomodate the extra load. They will definately slow the water flow down. The pump has to overcome the head pressure as well as the swing check. If they are on seperate loops I would say take the check valves out. The zone valves themselfs should keep from convexing.

Rusty

trollmaster

I agree with carierman in a residential setting I have never seen a need for a swing valve.Only high velosicty pumps use "swing valves" that I know about.

PIPES

So, the only real issue I read in your post is that the new boiler runs longer. You did not say a zone is too cold or too hot. I see the biggest difference in what you did was to go from a "high mass" boiler to a "low mass" boiler. That in itself explains the different run times.
I doubt your pumps are that far off sizing, unless your house is huge. What's the longest run in ft.?
As far as your swing valves, you need to clearify yourself. Are they swing checks to prevent back flow? or, Are the flow checks to prevent the zone from circulating by gravity?
If they are flow checks , yes you need them for each zone since you removed your zone valves.

Just for giggles and grins, What was your old boiler?